Best and worst things to buy in August

(MoneyWatch) Back-to-school shopping season launches this month with sales on everything from swimwear to barbecue gear. But there are also a handful of things you'd be crazy to buy in August, because they're sure to go on sale later in the year, according to bargain-hunting website DealNews.

Clothing: There are a dozen reasons to frequent retail stores in August, from end-of-the-season sales on hot-weather clothing to back-to-school sales and tax-holidays. For instance, Victoria's Secret is offering discounts of 25-50 percent on swimwear until August 7. J. Crew also has a sale on men's clothing and swimming apparel, according to FreeShipping.org.

Teen Vogue has designated August 11 as "Back to School Saturday," providing coupon codes to use that day (and sometimes longer) that offer discounts of as much as 50 percent. Gap is providing a 30 percent discount on both online and in-store purchases, while H&M, Kohls, and Guess are all offering 20 percent off and Quicksilver is giving a 25 percent discount. Express stores are offering $15 off a $30 purchase. (Check out Teen Vogue's BTSS page for details.)

It's also worth noting that 17 states, including New York, Virginia, and Florida, offer sales tax holidays, most of which occur in early August, according to CCH, a publisher of tax research. The tax holidays can get complex because each state has slightly different rules about what products are exempted from tax and when, but most include clothing and computers in their tax holidays, allowing shoppers to save anywhere from 3-8 percent at checkout. (Here's a state-by-state listing of what qualifies for tax exemptions.)

School supplies and dorm furniture: August is also a big month for sales on school supplies, from backpacks to composition notebooks. Need to outfit your dorm? Target (TGT) and PBTeenhave promotions on everything from bedding to desk lamps. Walmart (WMT) also typically stocks up on inexpensive dorm items, like futons and computer cases, according to DealNews.

Laptops: Many laptop manufacturers, from Apple (AAPL) to Hewlett-Packard (HPQ), offer back-to-school discounts to students. Some, including Apple, may require that you provide student ID to get the special promotions, which can include free software and rebates. State tax holidays also commonly apply to laptops, and on a $500 to $1,500 purchase that tax holiday can save a bundle.

Barbecue grills: Deals on BBQ grills traditionally heat up in August, too. Last year at this time, grills went on sale at Ace Hardware, Home Depot (HD), and Lowes (LOW). DealNews expects the trend to continue this August.

Big screen TVs: Name-brand television sets, ranging in size from 46" to 55". have suddenly gone on sale to prices unseen since Black Friday, according to editors at DealNews. A 46" LCD HDTV was selling for $449 on the site, while a 55" 3D HDTV was retailing for $999.

Worst deals

Phones & tablets: That said, do not be tempted to buy a smartphone or tablet in August, caution the editors at DealNews. New versions of both Amazon's (AMZN) Kindle and Apple's iPhone are expected out this fall. That's certain to cut the price on the models that are being sold today. If you're fine with an iPhone 4S, hang on until they're selling iPhone 5s, they advise. You may be able to save hundreds when the old version goes on sale.

Patio sets: You're already seeing sales on patio sets, but now is not the time to buy. Typically, the lowest prices on patio furniture register in October, when the time for sitting outside is long gone. Buy before Labor Day and you're almost certain to pay more.